1. Field of the Invention
The present invention relates to a gaming machine, and in particular, a reel assembly installed in the gaming machine. Such gaming machines include slot machines, poker machines, “pachislot” machines, and roulette machines. In addition, a mechanism of the reel assembly is used in other devices, such as a beverage vending machine having a roulette-like function.
2. Background Information
Some gaming machines such as slot machines and roulette machines are equipped with one or more mechanical reels or wheels (hereafter, collectively referred to as reels), which spin and randomly change the positions of symbols displayed on the surfaces thereof visible to players. Players may be able to win money (credits) or bonuses based upon the positions of the symbols when the reels come to a stop.
In general, electric motors, preferably stepping motors, rotate the reels under the control executed by a microcomputer. This allows the reels to spin at various rates, in the reverse direction, and with a high degree of precision, and thereby to produce various visual effects which entertain players.
Enhancing the visual effects requires more quick and accurate response from the spinning reels. In particular, the reels must come to a complete stop more quickly, i.e., vibrations of the reels must be quickly removed at a stop position. In some conventional reel assemblies, a weight disc is coupled to the shaft of a stepping motor through an elastic member (see Japan Patent Nos. 2533195, 2533196, and 2579691, and Japan Registered Utility Model No. 3093023). The rotational inertia of the weight disc reduces the circumferential vibrations of a reel at a stop position. The elastic member may be an elastomer or a spring, and allowed to be deformed in the circumferential directions of the shaft in the joint between the shaft and the weight disc. The stepping motor exerts torque on the weight disc through circumferential deformation of the elastic member, which absorbs circumferential vibrations of the weight disc (and accordingly, those of the reel) at a stop position. In another conventional reel assembly, an elastomer connects between the tip of the driving shaft of a stepping motor and the driven axis of a reel (see Japan Published Patent Application No. 2002-357245). The elastomer is allowed to be deformed in the circumferential directions. The stepping motor exerts torque on the driven axis through circumferential deformation of the elastomer, which absorbs circumferential vibrations of the reel at a stop position.
In order to enhance the visual effects, it is also important that axial vibrations of reels be reduced. In some conventional reel assemblies, a spring or stator coils of a stepping motor continuously pushes the rotor of the stepping motor in the axial direction by elastic or magnetic forces (see Japan Published Patent Application No. H06(1994)-284682 and U.S. Pat. No. 6,133,655). The elastic or magnetic forces reduce axial vibrations of the rotor and the shaft.
In the above-mentioned conventional reel assemblies, elastic members are used in the absorption of axial and circumferential vibrations of the reels at a stop position. However, the elastic forces of the elastic members and the vibration modes of the reels will easily vary in accordance with dimensional and assembly deviations in the components, the degrees of elasticity of the elastic members, operating conditions, ambient temperatures, and the like. Accordingly, the ability to reduce vibrations will vary widely in accordance with the assemblies and time. In addition, gaming machines (especially those used in casinos) require frequent model changes, and thus the structure of reel assemblies should be simple in order to enhance maintainability. This prevents the conventional reel assemblies from increasing the reliability of the spinning motions of the reels.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved reel assembly that reduces the axial and circumferential vibrations of a reel quickly and reliably at a stop position by using a simple structure, and thereby increasing the reliability of the spinning motions of the reel and enhancing the visual effects of a gaming machine equipped with the reel assembly. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.